The present invention relates to a vehicular indicator lamp, and more particularly to a structure for enhancing the appearance of such a lamp.
As shown in FIG. 9, generally a vehicular indicator lamp is provided with a light source bulb 2 having a filament 2a, a reflector 4 for reflecting light from the light source bulb 2 in the forward direction, and a front lens 6 provided forward of the reflector 4. In a conventional vehicular indicator lamp as shown in FIG. 9, the reflective surface 4a of the reflector 4 is formed as a paraboloid of revolution with respect to the optical axis Ax of the lamp fixture as the central axis. A plurality of fish eye lenses 6s are formed in the front lens 6. As a result, reflected parallel light from the reflective surface 4a is diffused by each of the fish eye lenses 6s in the vertical and lateral directions.
However, in the above conventional vehicular indicator lamp, as the visible structure is primarily simply a plurality of fish eye lenses 6s formed in the front lens 6, the resultant appearance of the lamp, when viewed from the front, looks plain, thus making the lamp fixture unattractive.
The present invention has been conceived in consideration of the above, and it is an object of the invention to provide an indicator lamp for a vehicle which is provided with an enhanced appearance by imparting originality to the lamp housing design.
The present invention achieves the above object by a novel design of the structure of the reflector and the front lens.
Namely, the vehicular indicator lamp according to the present invention is provided with a light source disposed on the optical axis of a lamp fixture, a reflector for reflecting light from the light source in the forward direction, and a front lens disposed forward of the reflector, wherein diffusion lens elements are formed at predetermined positions offset from the lamp fixture optical axis of the front lens, the reflective surface of the reflector is divided into an inner peripheral area and an outer peripheral area having a boundary formed by a lens element optical axis that is parallel to the lamp fixture optical axis and that passes through central positions of the diffusion lens elements, the inner peripheral area and the outer peripheral area approach a paraboloid of revolution that has the lamp fixture optical axis as a center axis on the lens element optical axis and are formed as a curved surface that curves forward of the paraboloid of revolution, and light from the light source is irradiated onto the diffusion lens elements as convergent light in a radial direction.
The front lens may be a normal outer lens or an inner lens provided inside the lamp fixture.
There is no particular limitation on the specific configuration of the diffusion lens element so long as it is a lens element that has a diffusing function formed at a predetermined position offset from the lamp fixture optical axis of the front lens. The predetermined position is not limited to a specific position, provided that, when the diffusion lens element is formed, the position can serve to divide the reflective surface of the reflector into an inner peripheral area and an outer peripheral area with the optical axis of the lens element as the boundary therebetween.
The convergent light in a radial direction refers to light that converges within a cross section that includes the optical axis of the lamp fixture.
In the vehicular indicator lamp according to the present invention, diffusion lens elements are formed at predetermined positions offset from the lamp fixture optical axis of the front lens. Moreover, the reflective surface of the reflector is divided into an outer peripheral area and an inner peripheral area, with the lens element optical axis that is parallel with the lamp fixture optical axis passing through a central position of the diffusion lens element as a boundary. The inner peripheral area and outer peripheral area approach a paraboloid of revolution revolved around the lamp fixture optical axis as the central axis on the lens element optical axis, and together they constitute a curved surface curving forward of the paraboloid of revolution. The above-described structure causes light from the light source to strike the diffusion lens element as convergent light in a radial direction, making it possible to obtain the following operational effects.
As convergent light in a radial direction is incident on the diffusion lens element, the diffusion lens element appears to shine more brightly compared with the case when parallel light is incident on the diffusion lens element, as is the case conventionally. Since the inner peripheral area and outer peripheral area constitute a curved surface approaching a paraboloid of revolution on the lens element optical axis, the image of the light source appears to be reflected at a central position of the diffusion lens element when seen from the front of the lamp fixture. In addition, the inner peripheral area and outer peripheral area are curved forward of the paraboloid of revolution. As the viewpoint changes from the front of the lamp fixture to the radial direction of the lamp fixture optical axis, the light source image moves from the central position of the diffusion lens element towards the opposite side to the direction in which the viewpoint changes.
Therefore, according to the present invention, it is possible to impart originality to the lamp fixture design, thus enhancing the appearance thereof.
In the above-described structure, assuming that the front surface of the diffusion lens element is formed as a non-spherical curve in which the radius of curvature Rh of a horizontal cross section and the radius of curvature Rv of a vertical cross section are set such that Rv greater than Rh, the transmitted light of the diffusion lens element forms a transversely extended light distribution pattern which extends further in the horizontal direction than in the vertical direction. As a result, it is possible to easily obtain the desired lamp fixture light distribution pattern.
It is possible to use only a single diffusion lens element. However, if diffusion lens elements are formed at a plurality of locations spaced at predetermined intervals in a circumferential direction centered on the lamp fixture optical axis, it is possible to realize the above-described appearance with a scattered placement. Therefore, the lamp fixture design can be provided with still more originality, and, as a result, the appearance of the lamp fixture can be even more enhanced.
With respect to the above-mentioned reflective surface, so long as the inner peripheral area and the outer peripheral area are formed to approach a paraboloid of revolution with the lamp fixture optical axis as the central axis on the lens diffusion optical axis and to constitute a curved surface curving forward of the paraboloid of revolution, there is no particular restriction as to the shape of the curved surfaces in the circumferential direction. However, if the reflective surface is formed from a plurality of reflective elements separated in the circumferential direction around the lamp fixture optical axis, each of these reflective elements is formed as a curved surface curving in the circumferential direction, and light from the light source is caused to strike each diffusion lens element as convergent light in the circumferential direction, light converging in the radial direction and in the circumferential direction strikes the diffusion lens elements. This enables the diffusion lens elements to appear to shine even more brightly. Moreover, by using this type of structure, the size of the diffusion lens element can be reduced or the distance between the reflective surface and the diffusion lens element can be shortened. It is thus possible to achieve an improvement in the originality of the lamp fixture design or to form a thinner lamp fixture. Here, the term xe2x80x9cconvergent light in the circumferential directionxe2x80x9d refers to the light that converges within a circumferential cross-section centered on the lamp fixture optical axis.
In the above structure, providing a condensing lens element on the lamp fixture optical axis of the front lens makes it possible to condense direct divergent light traveling forward from the light source, which is effectively used for light distribution control.